What is the alternative? Roads that become icy probably destroy cars as well, although in a more pinpoint kind of way. At least road salt doesn't cause a lot of fatalities.
As the article states, this system uses waste heat from a power plant transported via water.
That system is pretty tiny though. It just covers the main strip downtown. Maybe 6 blocks.
As a sibling points out, these systems use process heat, not electricity. U of M has a steam tunnel system in Ann Arbor, which I believe only covers sidewalks, not roads.